packerlayout.java

This is Layout manager for java using swing.

package com.jhlabs.awt;

import java.awt.*;
import java.util.*;

public class PackerLayout extends ConstraintLayout implements Direction {

	public final static Integer LEFT_TOP = new Integer((Direction.LEFT << 8) | Alignment.TOP);
	public final static Integer LEFT_CENTER = new Integer((Direction.LEFT << 8) | Alignment.CENTER);
	public final static Integer LEFT_BOTTOM = new Integer((Direction.LEFT << 8) | Alignment.BOTTOM);
	public final static Integer RIGHT_TOP = new Integer((Direction.RIGHT << 8) | Alignment.TOP);
	public final static Integer RIGHT_CENTER = new Integer((Direction.RIGHT << 8) | Alignment.CENTER);
	public final static Integer RIGHT_BOTTOM = new Integer((Direction.RIGHT << 8) | Alignment.BOTTOM);

	public final static Integer TOP_LEFT = new Integer((Direction.TOP << 8) | Alignment.LEFT);
	public final static Integer TOP_CENTER = new Integer((Direction.TOP << 8) | Alignment.CENTER);
	public final static Integer TOP_RIGHT = new Integer((Direction.TOP << 8) | Alignment.RIGHT);
	public final static Integer BOTTOM_LEFT = new Integer((Direction.BOTTOM << 8) | Alignment.LEFT);
	public final static Integer BOTTOM_CENTER = new Integer((Direction.BOTTOM << 8) | Alignment.CENTER);
	public final static Integer BOTTOM_RIGHT = new Integer((Direction.BOTTOM << 8) | Alignment.RIGHT);

	public final static Integer LEFT_TOP_FILL = new Integer((Direction.LEFT << 8) | Alignment.TOP | 0x80);
	public final static Integer LEFT_CENTER_FILL = new Integer((Direction.LEFT << 8) | Alignment.CENTER | 0x80);
	public final static Integer LEFT_BOTTOM_FILL = new Integer((Direction.LEFT << 8) | Alignment.BOTTOM | 0x80);
	public final static Integer RIGHT_TOP_FILL = new Integer((Direction.RIGHT << 8) | Alignment.TOP | 0x80);
	public final static Integer RIGHT_CENTER_FILL = new Integer((Direction.RIGHT << 8) | Alignment.CENTER | 0x80);
	public final static Integer RIGHT_BOTTOM_FILL = new Integer((Direction.RIGHT << 8) | Alignment.BOTTOM | 0x80);

	public final static Integer TOP_LEFT_FILL = new Integer((Direction.TOP << 8) | Alignment.LEFT | 0x80);
	public final static Integer TOP_CENTER_FILL = new Integer((Direction.TOP << 8) | Alignment.CENTER | 0x80);
	public final static Integer TOP_RIGHT_FILL = new Integer((Direction.TOP << 8) | Alignment.RIGHT | 0x80);
	public final static Integer BOTTOM_LEFT_FILL = new Integer((Direction.BOTTOM << 8) | Alignment.LEFT | 0x80);
	public final static Integer BOTTOM_CENTER_FILL = new Integer((Direction.BOTTOM << 8) | Alignment.CENTER | 0x80);
	public final static Integer BOTTOM_RIGHT_FILL = new Integer((Direction.BOTTOM << 8) | Alignment.RIGHT | 0x80);

	protected int hGap, vGap;

	public PackerLayout() {
		this(0, 0, 0, 0);
	}

	public PackerLayout(int hGap, int vGap, int hMargin, int vMargin) {
		this.hGap = hGap;
		this.vGap = vGap;
		this.hMargin = hMargin;
		this.vMargin = vMargin;
	}

	public void measureLayout(Container target, Dimension dimension, int type)  {
		int count = target.getComponentCount();
		if (count > 0) {
			Insets insets = target.getInsets();
			Dimension size = target.getSize();

			int minX = 0;
			int maxX = 0;
			int minY = 0;
			int maxY = 0;
			int position = Direction.RIGHT;
			int alignment = Alignment.CENTER;
			Rectangle[] sizes = new Rectangle[count];

			for (int i = 0; i < count; i++) {
				Component c = target.getComponent(i);
				if (includeComponent(c)) {
					Dimension d = getComponentSize(c, type);
					int x = 0;
					int y = 0;
					int w = d.width;
					int h = d.height;
					int cellX = 0;
					int cellY = 0;
					int cellW = w;
					int cellH = h;
					int fill = Alignment.FILL_NONE;
					
					if (i == 0) {
						maxX = w;
						maxY = h;
					} else {
						Integer n = (Integer)getConstraint(c);
						int v = 0;

						if (n != null)
							v = n.intValue();
						position = (v >> 8) & 0x7f;
						alignment = v & 0xff;
						if ((v & 0x80) != 0)
							fill = Alignment.FILL_BOTH;

						switch (position) {
						case Direction.LEFT:
						case Direction.RIGHT:
							switch (position) {
							case Direction.LEFT:
								x = minX - w - hGap;
								break;
							case Direction.RIGHT:
								x = maxX + hGap;
								break;
							}
							if (alignment == Alignment.TOP)
								y = minY;
							else if (alignment == Alignment.BOTTOM)
								y = maxY-h;
							else if (alignment == Alignment.CENTER)
								y = (minY+maxY-h)/2;
							break;
						case Direction.TOP:
						case Direction.BOTTOM:
							switch (position) {
							case Direction.TOP:
								y = minY - h - vGap;
								break;
							case Direction.BOTTOM:
								y = maxY + vGap;
								break;
							}
							if (alignment == Alignment.LEFT)
								x = minX;
							else if (alignment == Alignment.RIGHT)
								x = maxX-w;
							else if (alignment == Alignment.CENTER)
								x = (minX+maxX-w)/2;
							break;
						}
						minX = Math.min(minX, x);
						maxX = Math.max(maxX, x+w);
						minY = Math.min(minY, y);
						maxY = Math.max(maxY, y+h);
						switch (position) {
						case Direction.LEFT:
						case Direction.RIGHT:
							cellX = x;
							cellY = minY;
							cellH = maxY-minY;
							break;
						case Direction.TOP:
						case Direction.BOTTOM:
							cellX = minX;
							cellY = y;
							cellW = maxX-minX;
							break;
						}
					}

					sizes[i] = new Rectangle(x, y, w, h);
					Rectangle cell = new Rectangle(cellX, cellY, cellW, cellH);
					Alignment.alignInCell(sizes[i], cell, alignment, fill);
				}
			}

			if (dimension != null) {
				dimension.width = maxX-minX;
				dimension.height = maxY-minY;
			} else {
				for (int i = 0; i < count; i++) {
					Component c = target.getComponent(i);
					if (includeComponent(c)) {
						Rectangle r = sizes[i];
						c.setBounds(insets.left+hMargin-minX+r.x, insets.top+vMargin-minY+r.y, r.width, r.height);
					}
				}
			}
		}

	}

}